Individual differences in blood pressure (BP) change and BP elevation may be due in part to differences in the mechanisms regulating BP and BP reactivity. This project has two related components; 1) to continue longitudinal assessments of BP, body weight, height body fat distribution, etc, in a cohort of 817 subjects who have been examined semi-annually since 1978; and 2) to compare a "high risk" group of subjects (top quintile of systolic BP on three consecutive occasions) to a randomly selected comparison group to explore the relationships between plasma insulin and (BP) and BP reactivity as a function of obesity, fat distribution, catecholamine concentrations, and sodium flux. The proposed study will reexamine 817 healthy men and women aged 18-21 years who have participated in the Minneapolis Children's BP Study since 1978. We will assess the longitudinal predictors of BP change from childhood to young adulthood. The effects of somatic growth, body fat distribution, parental BP and obesity, and several health habits and behaviors on BP change will be estimated from repeated measures taken over the last 12 years. The second component of this study will evaluate the association between insulin and BP and BP reactivity in a group of subjects at risk for essential hypertension and a comparison group. We will quantitate glucose and insulin (fasting and after a glucose load), serum concentrations of epinephrine and norepinephrine, and sodium transport across the red blood cell membrane to better study their complex interrelationships with BP. Differences in obesity, fat distribution, physical activity and other covariates will be taken into account in the analyses. This study should provide valuable insight into mechanisms through which physiologic and biobehavioral factors interact to effect blood pressure regulation.